Driving mechanisms for electric circuit-breakers

ABSTRACT

912,948. Switches held set and freed mechanically. COQ, N. V. June 22, 1961 [July 2, 1960], No. 22676/61. Class 38 (5). In a switch similar to that of Specification 753,754, operation of the opening button 33a is prevented unless the opening spring 9 is tensioned and the switch is closed. Similarly, operation of a closing button 40 is prevented unless the closing spring 14 is tensioned. The button 33a acts to release a spring biased lever 28, movement of which to open the switch is prevented by links 41 ... 43 unless the contacts are closed. The button 40 likewise acts to release a lever 34, movement of which to close the switch is prevented by links 46...48 unless the spring 14 is strained and an intermediate member 10 connected thereto is latched at 26, 27. The member 10 is moved to its latched position to tension the springs by a piston 17.

y 16, 1963 H. A. HIDDE NIJLAND 3,098,134

DRIVING MECHANISMS FOR ELECTRIC CIRCUIT-BREAKERS Filed July 3, 1961 IN VENTOR HENDRiK A. H1005 NIJLAND BY f ATTORNEYS United States Patent 3,098,134 DRIVING MECHANISMS FOR ELECTRIC ClRCUIT-BREAKERS Hendrik A. Hidde Niiland, Laren, Netherlands, assignor to N.V. COQ, Utrecht, Netherlands, a corporation of the Netherlands Filed July 3, 1961, Ser. No. 121,533 Claims priority, application Netherlands July 2, 1960 2 Claims. (Cl. zen-7s The invention relates to a driving mechanism for an electric 'circuibbreaker adapted to be closed and opened with snap-action and comprising a movable part carrying one or more switching contacts, said movable part being connected to a movable intermediate member through at least one switching-off spring and a locking device for keeping said spring in tensioned condition, said intermediate member being in its turn connected through at least one switching-on spring and a second locking device for keeping said latter spring in tensioned condition to a stationary part of the mechanism and being arranged for such movement against the force of the switching-on and the switching-off springs as to bring all springs in their tensioned conditions simultaneously, and unlocking means adapted to release the locking devices from their locking positions to control the -circuit-breaker, the unlocking means for the switching-off spring consisting of a spring-loaded movable unlocking member held in tensioned position by a pawl mounted for operation from the outside.

A driving mechanism of this kind has been disclosed in the U.S. specification 2,784,270. In that driving mechanism a special device is provided which prevents that after the tensioning of all springs the intermediate memher is drawn back with a free movement towards its starting position when the locking device of the switchingoif spring is released before the one of the switching-on spring.

The invention has for its object to bring the unlocking members in their tensioned positions in a simple manner and to make a premature unlocking of the locking device of the switching-off spring impossible. It consists in that the unlocking member for the switching-off spring is brought into the tensioned position during the release of said spring and is held in said position as long as said spring is in its released condition, said unlocking member being only made free to be operated when the switchingofi spring is in its tensioned condition and the circuitbreaker is in its closed position. Also the unlocking means for the switching-on spring may consist of a spring-loaded movable unlocking member which is held in the tensioned position by a pawl mounted for operation from the outside, said unlocking member being brought into the tensioned position during the release of said switching-on spring and held in said position as long as said spring is in its released condition and said unlocking member being only made free to be operated when the switching-on spring is in its tensioned condition. In the last mentioned embodiment of the driving mechanism the unlocking member for the switching-on spring may be coupled with the intermediate member and the unlocking member for the switching-off spring may be coupled with the movable part of the circuit breaker. Consequently, in accordance with the invention at least the unlocking member for the switching-off spring is brought into its tensioned position by said spring itself and provisions are made that as long as said spring is in its tensioned condition and the circuit-breaker has not yet been closed the operation of the pawl of the unlocking member does not make said member operative.

The invention will be explained with the aid of the accompanying drawing which illustrates diagrammatically ice a driving mechanism according to the invention in three different operational positions.

In the drawing:

FIG. 1 is a diagrammatical view of said driving mechanism in the position, in which the switching-on spring and the switching-off spring are released and the circuitbreaker is in its open position.

FIG. 2 is a corresponding view of said mechanism in the position, in which both the switching-on spring and the switching-off spring are both tensioned and the circuit-breaker is still in its open position, and

FIG. 3 is a corresponding view of said mechanism in the position, in which the switching-on spring is released, the switching-off spring is still tensioned and the circuitbreaker is in its closed position.

In the drawing, 1 is a switching rod adapted to be moved axially up and down and to cooperate with fixed switching contacts 2, 3, to which may be connected in a way not shown the circuit to be closed or opened by the circuit-breaker. The switching rod 1 is connected through an insulator 4 to the arm 5 of a bell-crank 5, 7 adapted to be angularly reciprocated about the axis 6. In the off-position of the circuit-breaker shown in FIG. 1 the arm 7 rests against a stationary abutment 8. The arm 7 is connected by one or more tension springs 9 to the arm 10 of a two-armed lever 14 12 adapted to be angularly reciprocated about a shaft 11 and resting in the position shown in FIG. 1 with its arm 12 against a stationary abutment 13. The arm 12 is connected by one or more tension springs 14 to a stationary part 15 of the circuitbreaker.

The two-armed lever 1t 12 constitutes an intermediate member adapted to be operated by an operating mechanism. This mechanism consists of a hydraulic cylinder 16 provided with a piston which is connected with the arm 12. Through a liquid supply conduit 18 liquid may be forced into the left hand cylinder space and through the conduit 19 liquid may be discharged from the right hand cylinder space. A by-pass, in which a closable choke-valve 21 is provided, is designated by 20, so that the hydraulic cylinder 16 and the piston 17 may also be used as a clamping device.

The arm 7 of the bell-crank 5, 7 is also coupled with a locking bar 22 having 'a stop 23 adapted to cooperate with a stud 24- provided on the arm 10 of the intermediate member Iii, 12.

In order to tension the springs of the driving mechanism, so that the circuit-breaker may be closed and thereafter opened again the piston 17 is moved to the right, whereby the intermediate member 10, 12 is rotated counterclockwise and the springs 9 as well as the springs 14 are tensioned (FIG. 2).

Mounted on a stationary part of the circuit-breaker is a second locking bar 25 having a stop 26 adapted to cooperate with a stud 27 provided on the arm 12 of the intermediate member lti, 12. The locking bar 25 holds the intermediate member 1t 12 in the position, in which the springs 9 as well as the springs :14 are tensioned (FIG. 2). The locking bar 22 for the switching-off spring 9 may be released from its locking position by means of an unlocking member 28 constituted as an arm mounted for angular reciprocation about an axis 29. This arm is loaded by a spring 30 and connected to two other arms 31, 32. The arm 31 cooperates with its free end with a pawl 33 adapted to be operated from the outside and under certain circumstances to hold the unlocking arm 28 in the working position, in which the spring is tensioned. In the illustrated embodiment the pawl 33 is operated by means of a push-button 33a. A corresponding unlocking member and accessories are provided for the locking bar 25 of the switching-on spring 14. This unlocking member and these accessories are designated by 34, 35, 36, 3'7, 38, 39, 40.

The arm 32 of the unlocking member 28 is coupled through a system of rods 41, 42, 43 with the arm 7 of the bell-crank 5, 7 by means of a catch 44 provided at the free end of the rod 41. It appears from FIG. 1, that when the bell-crank 5, 7 rests against the abutment 8 in the open position of the circuit-breaker, the unlocking arm 28 is held by the catch 44 in the position in which the spring 30 is tensioned. In that position the arm 31 is a little bit free from the pawl 33 which then is in its locking position.

In like manner the unlocking arm 34 for the switchingon spring 14 is coupled with the arm 12 of the intermediate member 10, 12 by means of a system of rods 45, 46, 47 provided with a catch 48 engaging the arm 38. If the intermediate member rests against the abutment 13 the unlocking arm 34 is in its working position, in which the spring 36 is tensioned and said unlocking arm is held in said position by the catch 48. In that case the arm 37 is a little bit free from the pawl 39 which then is in its locking position.

If the circuit-breaker must be closed, first the intermediate member 10, 12 is brought by the piston 17 into the position shown in FIG. 2, in which position the springs 9 and 14 are tensioned. In that position the circuit-breaker is still in its open position and the bellcrank 5, 7 still rests against the abutment 8. The catch 44 then holds the unlocking arm 28 in its tensioned position, but the catch 48 leaves the unlocking arm '34 free to be operated. If the button 40 is pushed the pawl 39 is withdrawn and the spring 36 will move the unlocking arm 34 with a powerful blow against the locking bar 25, whereby the latter is lifted with its stop 26 from the stud 27 and the circuit-breaker is closed by the switching-on spring 14 through the intermediate member 10, 12 and the locking bar 22 which remains in the locking position. The driving mechanism will then assume the position shown in FIG. 3. During the clock-wise rotation of the intermediate member 10, 12 the unlocking arm 34 is returned by the catch '48 to the working position, in which the spring 36 is tensioned. Consequently, the switchingon spring 14 tensions also the spring 36 of the unlocking member. If the driving mechanism is in the position illustrated in FIG. 3, in which position the circuit-breaker is closed and the switching-on spring 14 is released but the switching-off spring 9 is still tensioned, the catch 44 leaves the unlocking arm 28 for the switching-off spring '9 free for operation.

If the closed circuit-breaker must be opened again the button 33a must be pushed, whereby the pawl 33 is withdrawn and the unlocking arm 28 is moved with a powerful blow by the spring 30 against the locking bar 22, so that the stop 23 thereof is lifted from the stud 24 and the switching-off spring '9 is allowed to release. The latter spring draws the bell-crank 5,7 carrying the switching rod 1, 4 back to the starting position, in which said bellcrank rests against the abutment 8 and the circuit-breaker is opened. Then the position shown in FIG. 1 is restored. During the releasing of the switching-01f spring 9, that means during the opening stroke of the switching rod 1, 4, the unlocking arm 28 is brought by the catch 44 in the working position, in which the spring 30 is tensioned.

-It appears from FIGS. 2 and 3 that, when both springs 9, 14 are tensioned (FIG. 2), the pushing of the pushbutton 33a for the withdrawal of the pawl 33 of the unlocking arm 28 has no effect, since said unlocking arm is then held in its tensioned position by the catch 44. If

the circuit-breaker is closed (FIG. 3), the pushing of the button 40 has no effect, since the unlocking member 34 is then locked in its tensioned position by the catch 48. Thus a faulty operation of the circuit-breaker by hand is prevented. Another effect of the invention is that the springs of the unlocking members are tensioned by the main switching springs of the circuit-breaker.

It is observed that it is not necessary that the switchingon elements of the driving mechanism are constructed in [the illustrated manner, that means in the same way as the switching-off elements of the driving mechanism. The elements of the driving mechanism for the switching-on or closing process may also be constructed in the manner as disclosed in the U8. specification 2,784,270.

What I claim is:

1. A driving mechanism for an electric circuit-breaker, comprising in combination a movable part, at least one switching contact carried by said movable part, a movable intermediate member, at least one switching-off spring, a first locking device for keeping said spring in tensioned condition, said switching-off spring and said first locking device connecting said movable part with said intermediate member, at least one switching-on spring, a second locking device for keeping the latter spring in tensioned condition, said switching-on spring and said second locking device connecting said intermediate member with a stationary part of the circuit-breaker, an operating member acting on the intermediate member and adapted to bring all springs in their tensioned condition and both locking devices in their locking positions simultaneously by moving said intermediate member against the forces of all springs, a first unlocking means and a second unlocking means for the release from their locking positions of said first and said second locking devices respectively, said first unlocking means including a spring loaded movable unlocking member, a pawl holding said unlocking member in a spring loaded working position until the pawl is released from outside the circuit breaker, and a lost motion coupling interconnecting said unlocking member and said movable part so to force and hold said unlocking member to said working position when the movable part is moved to open the switching contact and to prevent the release of said pawl from releasing said unlocking member from said working position, said lost motion coupling freeing the unlocking member so that it can be released by said pawl from said working position when said switching contact is closed.

2. A driving mechanism for a circuit breaker as claimed in claim 1, comprising in addition a second spring-loaded movable unlocking member, said second unlocking member forming a part of the said second unlocking means for the switching-on spring, a second pawl adapted to hold said second unlocking member in a tensioned working position and to be operated from outside the circuitbreaker, and a second lost motion coupling interconnecting the second unlocking member and the movable intermediate member so as to force said second unlocking member to its said working position when said intermediate member is moved to close said switching contact or to open said contact when all springs are eased, said second lost motion coupling freeing the second unlocking member for release by the second pawl when the intermediate member is in its position in which all springs are tensioned.

References Cited in the file of this patent UNITED STATES PATENTS 2,784,270 Nijland Apr. 13, 1954 

1. A DRIVING MECHANISM FOR AN ELECTRIC CIRCUIT-BREAKER, COMPRISING IN COMBINATION A MOVABLE PART, AT LEAST ONE SWITCHING CONTACT CARRIED BY SAID MOVABLE PART, A MOVABLE INTERMEDIATE MEMBER, AT LEAST ONE SWITCHING-OFF SPRING, A FIRST LOCKING DEVICE FOR KEEPING SAID SPRING IN TENSIONED CONDITION, SAID SWITCHING-OFF SPRING AND SAID FIRST LOCKING DEVOCE CONNECTING SAID MOVABLE PART WITH SAID INTERMEDIATE MEMBER, AT LEAST ONE SWITCHING-ON SPRING, A SECOND LOCKING DEVICE FOR KEEPING THE LATTER SPRING IN TENSIONED CONDITION, SAID SWITCHING-ON SPRING AND SECOND LOCKING DEVICE CONNECTING SAID INTERMEDIACT MEMBER WITH A STATIONARY PART OF THE CIRCUIT-BREAKER, AN OPERATING MEMBER ACTING AN THE INTERMEDIATE MEMBER AND ADAPTED TO BRING ALL SPRINGS IN THEIR TENSIONED CONDITION AND BOTH LOCKING DEVICES IN THEIR LOCKING POSITIONS SIMULTANEOUSLY BY MOVING SAID INTERMEDIATE MEMBER AGAINST THE FORCES OF ALL SPRINGS, A FIRST UNLOCKING MEANS AND A SECOND UNLOCKING MEANS FOR THE RELEASE FROM THEIR LOCKING POSITIONS OF SAID FIRST AND SAID SECOND LOCKING DEVICES RESPECTIVLY, SAID FIRST UNLOCKING MEANS INCLUDING A SPRING LOADED MOVABLE UNLOCKING MEMBER, A PAWL HOLDING SAID UNLOCKING MEMBER IN A SPRING LOADED WORKING POSITION UNTIL THE PAWL IS RELEASED FROM OUTSIDE THE CIRCUIT BREAKER, AND A LOST MOTION COUPLING INTERCONNECTING SAID UNLOCKING MEMBER AND SAID MOVABLE PART SO TO FORCE AND HOLD SAID UNLOCKING MEMBER TO SAID WORKING POSITION WHEN THE MOVABLE PART IS MOVED TO OPEN THE SWITCHING CONTACT AND TO PREVENT THE RELEASE OF SAID PAWL FROM RELEASING SAID UNLOCKING MEMBER FROM SAID WORKING POSITION, SAID LOST MOTION COUPLING FREEING THE UNLOCKING MEMBER SO THAT IT CAN BE RELEASED BY SAID PAWL FROM SAID WORKING POSITION WHEN SAID SWITCHING CONTACT IS CLOSED. 